Perhaps you should try some spelling variations:
dau luan » dan luan, dat luan, khau luan
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
qua dau » qua da, qua bau, qua dan
luan va » luan van, luat va
va hanh » van hanh, va thanh, va danh
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua
de cua » le cua, te cua, dieu cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ma hoi. hieu qua dau luan va hanh ((vi cua) or (de cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. hieu qua dau luan va hanh ((vi cua) OR (de cua)) tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoi. hieu qua dau luan va hanh ((vi cua) or (de cua)) tre*.